Industrial printers are typically large format machines capable of printing on different substrates of variable sizes and thickness. These printers may be suitable for printing, for example, paper having a thickness of tenth of a millimeter and cardboard sheets having a thickness of 8-9 mm. The substrate is placed on a large format table and moves along the X-axis. In order to ensure the quality of printing, the print head moves along the Y-axis in close proximity, typically one to two millimeters, to the substrate.
Fox each substrate, it is desirable to adjust the distance between the print head and the upper surface of the substrate according to its thickness. The adjustment of that distance may be achieved by either moving the print head or the table in a vertical direction. Moving the print head, however, may adversely affect the quality of printing.
Printing machines usually have mechanisms for conveying print material. In wide-format digital printing machines operating in step-mode, and in particular high-resolution printing machines, a need currently exists for a mechanism to move a substrate forward while maintaining accurate register.
The use of a vacuum table for moving a substrate is known. The continual disconnecting and reconnecting of the print material from and to the table leads, however, to a cumulative loss in registration accuracy.